Cleaning method and material



Oct. 23, 1951 F. R. PERRY CLEANING METHOD AND MATERIAL THEREFOR original Filed April 14, 1944 TL-111.7. Q-

Reissued Oct. 23, 1951 UNITED STATES PATENT OFFICE Re. A23,422

:CLEANING METHOD AND MATERIAL THEREFOR Matter enclosed in heavy bracketsv I: j appears in the original patent but forms no partV of this reissue specification; matter printed in italics indicates the additions made by reissue.y

11 Claims.

My present invention relates to method and apparatus for cleaning by abrasives and to novel materials therefor.

The pistons, c :yliruiersy and other parts of internal combustion engines, for instance, become covered with adhering carbonaceous deposits which must be removed and which chemical solvents., vapor cleaners and mild alkali sprays are incapabley of completely removing. Since many of such parts are usuallymade of aluminum alloys, strong alkali or acid solutions cannot be used upon them. While sand blasting is capable of removing such deposits, it cannot be safely employed because it produces surface pits and roughness which destroy the usefulness of the parts. rJifhus it has been necessary to remove such deposits by hand scraping and rubbing with abrasive Woolsand cloths, which operations are impracticable because of the length of time required to carry them out.

I have heretofore proposed the use, in air blast equipment, of small particles of starch killed dehydrated cereal grains, and while that material is effective in that it provides an eiective cleaning operation, it is relatively expensive in that the grain must be first specially treated and inA that the particles quickly become so pulverulent or powdered that they are ineffective as an abrasive.

I have found that I can produce a highly efcient cleaning operation by utilizing, in an air blast, a hard nut shell ground or cracked into particles of relatively small size. More particularly I have found that black walnut shells ground or cracked into relatively small particles to be peculiarly suitable in that such materialy is rela'- tvely inexpensive, plentiful as waste, is not sufi-l'- ciently hard to pit or roughen metal surfaces, althoughit is hard enough to produce an effective cleaning operation. Such particles also last through aA large number of cleaning operations and produce substantially no dust.

It is therefore one of the principal objects of my present invention to provide a novel method of removing carbonaceous deposits from metal.

Another` object is to provide a new and elcient abrasive cleaning material.

Another object is to provide a cleaning method and material using ground or cracked black walnut shells or equivalent materials.

A still further object is to provide a novel apparatus for cleaning by air blasting.

By way of explaining my invention, I shall now describe a particular embodiment thereof, although the invention in its broader aspects is not to be confined to the details to be described since in its broader aspects as defined by ther accompanying claims it is susceptible of being modified in manners which the following description will suggest to those skilled in the art.

For purposes of the following descriptionY I shall refer to the accompanying drawings, in which:

Fig. 1 illustrates in perspective some of the4 abrasive particles;

Fig. 2 is a side elevation, partly broken away,

of an apparatus embodying my invention;

Fig. 3 is an enlarged longitudinal section of the mixing element;

Fig. 4 is an enlarged section taken on line 4.-4 of Fig. 2; and

Fig. 5 is a fragmentary lenlarged section of thel discharge end of thenozzle element.

In the drawing, Fig. 1, I show granules or pel-- lets 5, formed by grinding or cracking thedried shells of black walnuts. pellets may be varied somewhat, it is desirable that they be cracked or ground in such manner as to present relatively sharp edges and to a 10-30 mesh screen size, an optimum sizebeing 10-15 mesh.

In carrying out my operation I prefer to utilizel apparatus comprising a cabinet 'I open, at its front and having bottom wallsy B which converger to anl outlet neck 9. A work-supporting bracket l0 may be secured in the cabinet and a suction conduit l2 communicates with the interior of the cabinet at a point adjacent the bracket IIJV through a flaring portion l5. Conduit I2 communicates with the intakeoi a suction fan I1 of conventional construction and the discharge-outlet I8 from the fan leads to a waste depository not shown.

A conduit 2D has its inlet neck communicating with the outlet end of neck 9 through a damper member 22 to admit air to the conduit. As best shown in Fig, 4, the member 22 has a wall 24 provided with an opening 25 and adapted to be open and closed by rotatable damper 26.

The outlet end of conduit 20 communicates with a suction chamber C in a mixing chamber 30. The mixing member comprises a tubular medial portion 3| having a reduced diameter discharge end to receive a flexible hose 33. A nipple 34 extends into the inlet end of the member 30, having a restricted discharge passage 35 communicating with the bore of member 30 at one end of chamber C, so that air under pressure discharged through nipple 34 from a hose 35 communicating with a conventional compressor While the sizeof the- I1 will create a vacuum in chamber C tok draw the abrasive particles into the air line. A nozzle 40 is secured on the discharge end of the h-ose 33.

My cleaning method is carried out and the apparatus operates as follows:

A supply of pellets is placed in the bottom portion of cabinet 1 and the article to be cleaned, here designated W, is placed upon the bracket Il] or it may be merely manually held in the cabinet. By opening the valve 45 controlling line 36, a stream of air under pressure passes from the compressor and is discharged onto the work W through nozzle 40. The vacuum created in chamber C draws the desired quantity of the pellets 5 through line 20 into the air stream, which pellets are projected against the work W with the force of the air stream. The quantity of pellets introduced to the air stream depends, of course, upon the air pressure and upon the degree of opening of the damper 2B. The pellets being relatively light in weight, too great a quantity of them would be drawn into the air Ystream if the 'damper were completely closed, and yet a suicient air pressure must be used to project the pellets against the work With suitable abrasive force.

My apparatus is, of course, suitable for carrying out a cleaning operation wherein other types of pulverized abrasives are used which may be susceptible of vbeing broken up into powder or dust form by impact with the work. Even with the use of pellets formed of ground or cracked dried black walnut shells some relatively small fragments will be broken orf the main pellet forni, which fragments are too small to be useful and which should not be permitted to return 'to the storage supply of the pellets in the lower part of the cabinet. Thus, to prevent any powdered material from being returned to the main pellet supply in the lower part of the cabinet, I provide conduit l2 and suction fan l1, which fan will draw off any powdered material which does not readily drop into the lower part of the cabinet by gravity against the action of the suction fan, so that all pellets in the lower part of the cabinet are maintained of suitable size for eicient operation.

Pellets formed of cracked or ground 4dried nut shells, While suciently hard to remove carbonaceous deposits from metal, are sufliciently resilient that they do not pit or indent the metal. While I have found ground or cracked black walnut shells to be preferable, my invention in its broader aspects contemplates the use of pellets of other types of ground or cracked nut shells having equivalent characteristics.

I claim:

1. The method of cleaning metal articles which consists of projecting thereagainst a stream of iluid under pressure carrying, in suspension therein, pelletized nut shells having the hardness of black Walnut shells.

2. The method of cleaning metal articles 'which consists of projecting thereagainst a stream of i'luid under pressure carrying, in suspension therein, pelletized black walnut shells.

3. An abrasive material for use in air blasts for cleaningr metal comprising pelletized nut shells having the hardness of black walnut shells.

4. An abrasive material for use in air blasts for, cleaning metal comprising pelletized black walnut shells.

5. The method of cleaning metal articles which consists of projecting thereagainst a stream of fluid under pressure carrying, in suspension therein, pelletized nut shells, having the hardness of black walnut shells, ground to a screen siee of 10-30 mesh.

6. Tlhe method 'of cleaning metal articles which consists ,of projecting` thereagainst a stream of fluid under pressure carrying, in suspension therein, pelletized nut shells, having the hardness of black walnut shells, ground to a screen size of 10-15 mesh.

7. The method of cleaning metal articles which consists of projecting thereagainst a stream of fluid under pressure carrying, in suspension therein, pelletized black walnut shells having a screen size of 10-30 mesh.

8. The method of cleaning metal articles which consists of projecting thereagainst a stream of fluid under pressure carrying, in suspension therein, pelletized black walnut shells'having a screen size of 10-15 mesh.

9. An abrasive material ,for use in air blasts for cleaning metal comprising pelletized nut shells presenting relatively sharp edges and having the hardness of black walnut shells, and having a screen size of 10-30 mesh.

10. An abrasive material for use in air blasts' lfor cleaning metal comprising pelletized black walnut shells having a screen size of 10-30 mesh. 11. An abrasive material for use in air blasts for cleaning metal comprising pelletized black walnut shells having a screen size of 10-15 mesh.

FRANK R. PERRY.

REFERENCES CITED The following references are of record in the le of this patent `or the original patent:

UNITED STATES PATENTS 

